adding 3rd color to bicolor LED

Discussion in 'General Electronics Chat' started by SacredGroove, May 30, 2011.

  1. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    Hey everyone, I have a question about how to get a blend of the two colors of a bicolor LED. When I have both lit, they look more/less like two colors, individually. Is there some kind of lens I could use to help blend the colors better.

    FWIW, the LED is red/green, common cathode, and I'm trying to achieve amber-orange.

    Thanks in advance.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    The colors will blend if you use a difuse glass in front of the led.
    You can also rub the led itself with sone fine sand paper.(if you have some spare to try).

    Bertus
     
  3. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    Thanks for the suggestions guys. Tape, I think will be too tedious, for this application anyhow.

    How about matte or flat clear spray?
     
  4. HarveyH42

    Active Member

    Jul 22, 2007
    425
    5
    Don't they blend, when fed AC? Normally one color lights with the voltage applied in one direction, the other color, when reversed, both light when fed AC, but alternates so fast your head blends the two colors.
     
  5. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
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    I sometimes put a layer or two of thin white translucent plastic shopping bag material over an LED to diffuse it. If you have the space, using one diffuser close to the LED and one farther away (double diffusion) works well. If you don't have much space, grinding the dome on the top of the LED flat will help by defocusing the light into a wider dispersion pattern.

    There are commercial plastic diffusion films. You may see them over the LEDs on a LCD backlight array. Here's one of them: http://www.optigrafix.com/downloads/data_sheets/lightdiffuser.pdf.
     
  6. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    It's not bipolar. There's a common cathode with two anodes.
     
    Last edited: May 30, 2011
  7. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
    12
    0
    Can these be used on a 3mm led bulb? That seems kinda tedious, albeit a good idea.

    Honestly, I was hoping for some kind of lens to do the same job. That way I could drill a slightly bigger hole for the lens to clip into, and the bulb could sit inside the lens.
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    I think it is a cheap Chinese dual LED where one LED shines over here and the other LED shines over there.
    A half-decent Name-Brand dual LED has both LEDs shining forward to the same place.
     
  9. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    Suppose it is a cheap LED. Would you point me to one that isn't cheap? I get most of my LEDs from performance-pcs.com.
     
  10. retched

    AAC Fanatic!

    Dec 5, 2009
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    Agreed. often the cheap bi-color LEDs cannot light both at the same time. I have some cheap blue/red LEDs that can only light one at a time. And they are horribly aimed.
     
  11. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    Perhaps, the aim is off a bit, but both colors will light at the same time.
     
  12. Audioguru

    New Member

    Dec 20, 2007
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    A cheap LED has a narrow beam angle so it appears bright when it shines directly at you.
    But a good LED is bright with a wide beam angle. Then if it is a dual LED its colours add together properly.
     
  13. SacredGroove

    Thread Starter New Member

    Mar 14, 2010
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    OK, makes sense. The colors are definitely brighter from straight on. So I should look for a wider focused beam then. Or I just resort to three different LEDs.
     
  14. KJ6EAD

    Senior Member

    Apr 30, 2011
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  15. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
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    I'm using " Super Bright 2 Color LED Blowout [ Box of 200 , red- green ] #G17617, @ $6.95, from The Electronic Goldmine. nice orange.
     
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